import React, {Component} from 'react';
import PubSub from 'pubsub-js'
import './index.css'

export default class List extends Component {

  state = {   // 初始化状态
    users: [],    // users初始值为数组
    isFirst: true,    // 是否为第一次打开页面
    isLoading: false,     // 标识是否处于加载中
    err: ''     // 存储请求相关的错误信息
  }

  componentDidMount() {
    this.token = PubSub.subscribe('atguigu', (msg, stateObj) => {
      this.setState(stateObj)
    })
  }

  componentWillUnmount() {
    PubSub.unsubscribe(this.token)
  }

  render() {
    const {users, isFirst, isLoading, err} = this.state
    return (
      <div className="row">
        {
          isFirst ? <h2>欢迎使用，输入关键字，随后点击搜索</h2> :
          isLoading ? <h2>Loading...</h2> :
          err ? <h2 style={{color: 'red'}}>{err}</h2> :
          users.map((userObj) => {
            return (
              <div key={userObj.id} className="card">
                <a href={userObj.html_url} target="_blank">
                  <img src={userObj.avatar_url} style={{width: '100px'}}/>
                </a>
                <p className="card-text">{userObj.login}</p>
              </div>
            )
          })
        }
      </div>
    );
  }
}